Bugfixes:
- Fix performance regression due to suboptimal index in the quadstore
- Fix messing up with IRI ending with a /
- Fix error in World cloning
- Fix the addition of Thing in class's parent when redefining a class with Thing as the only parent
- Fix inverse_resctriction()
- Add error message when creating an existent quadstore

Use Class.property.indirect() for indirect Class property (instead of Class.property)

Add reload and reload_if_newer parameters to Ontology.load()

search() is now much faster on properties that have inverse

Add shortcut for SOME ConstrainedDatatype: e.g. age >= 65

Bugfixes:
- Fix creation of an individual that already exists in the quadstore
- Fix missing import of EntityClass in class_construct.py
- Fix World.save() with RDF/XML format
- Fix Thing.subclasses() and Thing.descendants()
- Fix ontology's update time for ontologies created de novo in Python with Owlready
- Fix reasoning when asserting new parents with equivalent classes

Bugfixes:
- Align Python floats with xsd:decimal rather than xsd:double, finally, because decimal accepts int too
- Fix Class.instances() so as it returns instances of subclasses (as indicated in the doc)
- Fix direct assignation to Ontology.imported_ontologies
- Fix a bug in reasoning, when adding deduced facts between one loaded and one non-loaded entity
- Fix search(prop = "value") when value is a string and the ontology uses localized string